Bug#856449: libgtk-3-0: Dragging on a touchpad without buttons with 2 fingers no longer possible

[Rostislav Pehlivanov]

Package: libgtk-3-0
Version: 3.22.9-1
Severity: normal

Dear maintainer,

Since upgrading to version 3.22.9, dragging operations cannot be performed using
two fingers on a touchpad without any exposed buttons (e.g. where pushing the surface
itself is the button). What happens now is that the cursor remains stationary and
instead a scroll up/down action is sent.

Although this might sound like a libinput issue, this issue didn't occur after I upgraded
(and rebooted) libinput to 1.6.2 but only after I upgraded libgtk-3-0 from 3.22.8 to 3.22.9.

Although lately some rather annoying (but still ignorable) issues have happened with changes
in behaviour (in both libinput and gnome), this issue breaks workflow when selecting any text,
since continuously pressing and dragging on the touchpad reduces precision and increases
errors.

-- System Information:
Debian Release: 9.0
  APT prefers unstable
  APT policy: (500, 'unstable'), (1, 'experimental')
Architecture: amd64 (x86_64)
Foreign Architectures: i386

Kernel: Linux 4.10.0-youmu+ (SMP w/8 CPU cores; PREEMPT)
Locale: LANG=en_GB.UTF-8, LC_CTYPE=en_GB.UTF-8 (charmap=UTF-8)
Shell: /bin/sh linked to /bin/dash
Init: systemd (via /run/systemd/system)

Versions of packages libgtk-3-0 depends on:
ii  adwaita-icon-theme                      3.22.0-1
ii  hicolor-icon-theme                      0.15-1
ii  libatk-bridge2.0-0                      2.22.0-1
ii  libatk1.0-0                             2.22.0-1
ii  libc6                                   2.24-9
ii  libcairo-gobject2                       1.14.8-1
ii  libcairo2                               1.14.8-1
ii  libcolord2                              1.3.3-2
ii  libcups2                                2.2.1-8
ii  libepoxy0                               1.3.1-2
ii  libfontconfig1                          2.11.0-6.7+b1
ii  libfreetype6                            2.6.3-3+b2
ii  libgdk-pixbuf2.0-0                      2.36.5-2
ii  libglib2.0-0                            2.51.0-2
ii  libgtk-3-common                         3.22.9-1
ii  libjson-glib-1.0-0                      1.2.2-1+b1
ii  libpango-1.0-0                          1.40.4-1
ii  libpangocairo-1.0-0                     1.40.4-1
ii  libpangoft2-1.0-0                       1.40.4-1
ii  librest-0.7-0                           0.8.0-2
ii  libsoup2.4-1                            2.56.0-2
ii  libwayland-client0                      1.12.0-1
ii  libwayland-cursor0                      1.12.0-1
ii  libwayland-egl1-mesa [libwayland-egl1]  17.0.0-1
ii  libx11-6                                2:1.6.4-3
ii  libxcomposite1                          1:0.4.4-2
ii  libxcursor1                             1:1.1.14-1+b1
ii  libxdamage1                             1:1.1.4-2+b1
ii  libxext6                                2:1.3.3-1
ii  libxfixes3                              1:5.0.3-1
ii  libxi6                                  2:1.7.9-1
ii  libxinerama1                            2:1.1.3-1+b1
ii  libxkbcommon0                           0.7.1-1
ii  libxml2                                 2.9.4+dfsg1-2.2
ii  libxrandr2                              2:1.5.1-1
ii  shared-mime-info                        1.8-1

Versions of packages libgtk-3-0 recommends:
ii  libgtk-3-bin  3.22.9-1

Versions of packages libgtk-3-0 suggests:
ii  gvfs             1.30.3-1
ii  librsvg2-common  2.40.16-1+b1

-- no debconf information